[1]: 23 The Marukis took on heavy themes such as the atomic bomb, genocide, and environmental pollution, and constantly voiced their anti-war and peace message through their art.
[4]: 104–129 From 1937 to 1938, Maruki was transferred to Moscow as a private tutor to the child of diplomats, through the recommendation from her colleague at the Ichikawa Municipal Higher Elementary School, Fumiko Hirano.
[4]: 130–159 According to Yukiko Yokoyama, "This coincided with Stalin’s Great Purge, but she was isolated from such horrors, and during this peaceful life, surrounded by clear rivers and white birch groves, she succeeded in producing one sketch a day.
"[3] After returning to Japan in 1938, Maruki worked again as a substitute teacher at Ichikawa Municipal Higher Elementary School from spring until August, and then lived in the artists’ community, Ikebukuro Montparnasse in Tokyo.
From January 1940, Maruki spent six months travelling alone across the Palau and Yap islands of Micronesia in the South Seas Mandate, then under Japanese rule.
"Taking inspiration from the nature of the tropics, the coral reef seas and the lifestyles of the islanders, [Maruki] produced several oil paintings characterised by bold lines and colours.
In 1941 Toshi Maruki was sent again to Moscow for six months as a private tutor to the child of the Japanese Counselor in Soviet Union, Haruhiko Nishi.
[4]: 207–214 Toshi Maruki produced war propaganda picture books for children based on her South Sea travels.
In 1947, Toshi Maruki joined the Avant-Garde Art Association (Zen’ei bijutsu kai) where she exhibited her Emancipation of Humanity (Kaihō sarete iku ningeisei).
In February 1950, the Marukis presented their collaborative work, August 6th (Hachigatsu muika; later to be known as Ghosts or Yūrei, the first part of the Hiroshima Panels) at the 3rd Japan Indépendants Exhibition.
[9] The Exhibition of the Hiroshima Panels continued to be held in other parts of Europe including the Netherlands and Italy until touring East Asia and Oceania starting in 1956.
In 1995, Lawrence S. Wittner of the State University of New York at Albany recommended the Marukis to the selection committee as a candidate for the Nobel Peace Prize.